Fertilizer and water is an important link in the breeding process. However, in production practice, especially in the early stage of breeding, it is often difficult to fertilize and water. The reasons and solutions of the difficulty in fertilizer and water are introduced as follows:

1. Reason: Too much lime was used in pond cleaning, resulting in high pH value of pond water and sediment in a short time, which made it difficult for fertilizer to exert its fertilizer efficiency, thus making it difficult to fertilize and water;

Solution: After cleaning the pond with large dose of quicklime, it is best to wait for about half a month, and then apply fertilizer after the pH of the pond returns to normal. Or use weak acids such as acetic acid, boric acid, citric acid, etc. to reduce the pH value to the normal range and feed water and fertilize.

2. Reason: The low water temperature in the early stage limited the propagation speed of algae, which made it difficult to fertilize and water;

Solution: Fertilize after continuous sunny days and strong sunshine, or smear soybean milk and seaweed powder to enhance the photosynthesis of algae and stimulate its reproduction.

3. Reason: The content of heavy metals in water exceeds the standard, and harmful bacteria multiply in large numbers, which makes fertilization and watering difficult;

Solution: Disinfect the water with disinfectants such as chlorine dioxide and povidone iodine, then rehydrate it with toxic substances such as EDTA and sodium thiosulfate, and then apply fertilizer after 2-3 days.

4. Reason: The sediment is hardened and the material exchange with the water body is stagnant, which makes it difficult to fertilize and water;

Solution: Use EM live bacteria preparation the next day after fertilization, or mix organic fertilizer with EM live bacteria preparation and soak for 1-2 hours before application.

5. Reasons: There are many zooplankton in the water, algae species are basically eaten, and fertilization and watering are difficult;

Solution: in the fry stage, the feeding amount can be reduced to promote the fry to eat a lot of zooplankton; In the growing period, abamectin can be used for local killing, and then some fresh water sources can be introduced for fertilizer and water.

6. Reason: There is more moss at the bottom of the pond, and most of the fertilizer applied is absorbed and utilized by the moss, so it is difficult to fertilize and water;

Solution: In seedling stage, gypsum powder, plant ash or deepening water level can be used to block the photosynthesis of moss to eliminate moss. During the breeding period, drugs such as surfactants can be mixed with sand for local killing, and then water sources with algae seeds can be introduced to fertilize water.

7. Reason: The transparency of the water body is low, and the impurities suspended in the water body are easy to adsorb and complex the effective components in the fertilizer, which hinders the photosynthesis of algae, thus making it difficult to fertilize and water;

Solution: You can choose a water quality improver with polymer or alum as the main component to clarify the water quality and improve the transparency of the water body, and then apply organic fertilizer. When applying organic fertilizers such as chicken manure, pig manure and rapeseed meal. Be sure to fully show filial piety first, and cooperate with EM bacteria or Bacillus to fertilize water when applying to inhibit the reproduction and growth of harmful algae.

8. Reason: The water body and its surrounding waters are short of natural algae species, making fertilization and watering difficult;

Solution: artificially supplement the water with beneficial algae species, such as introducing some pond water with algae species, and then fertilizing.

9. Reason: The nutrient elements in the applied fertilizer are not comprehensive or the ratio is not suitable, which is easy to cultivate bad water color;

Solution: If traditional fertilizers such as chicken manure, rapeseed cake and compound fertilizer are used, it is best to use EM bacteria or compound Bacillus together. Biological fertilizers containing potassium and phosphorus can also be used to fertilize water.

10. reason: excessive reproduction of harmful algae in water inhibits the growth and reproduction of beneficial algae;

Solution: Replace the surface water of 10-20cm, and then apply a reasonable proportion of biological fertilizer to fertilize the water.